In the manufacture of a rigid body, for instance a brake pad for a brake shoe, from a mass of loose and fluent particles, it is typically necessary to preform the mass into a vaguely coherent workpiece that is held in a throughgoing passage of a holder. A transfer plunger pushes the workpiece out of its passage into a cavity of a die and the holder is moved out of the way and replaced by a counter piston carrying a backing plate. Then a plunger defining the floor of the die cavity is raised under considerable pressure while the mass in the die is heated to form it into a rigid body that adheres to the backing plate. Subsequently the press is opened and the finished brake shoe is taken out and sent on to the next manufacturing stage.
Such a product is typically made in a variety of sizes so that the press must be adapted to different workpieces. The press capacity can vary from 30t to 100t depending on the type of workpiece being made, with even smaller and greater press capacities being possible. When multiple dies are used the loading of the press and its general operation are normally unsatisfactory, involving using the press at much less than its capacity. In addition with such multiple dies if any one die cavity is not filled to the exact same extent as the other die cavities, the whole batch of workpieces is typically spoiled.